1. Field of the Invention
The invention relates to a cosmetic and/or dermatological preparation for topical application based on a water-containing emulsion in the form of solid, semisolid and/or dimensionally stable spheres, spheroids or otherwise shaped bodies containing essentially waxes, emulsifiers, natural and/or synthetic polymers and/or mixtures thereof. The preparation melts upon rubbing and/or distribution on the skin and/or the hair and/or becomes completely or partially liquid due to shear forces and/or mixes with the lipids of the skin sebum and/or dissolves therein.
2. Discussion of Background Information
Tablets for peroral pharmaceutical use have been known since the 19th century at the latest. These are single-dose solid medicaments which are formed from dry powders, crystals or granules under high pressure and in the presence of auxiliaries (Rudolf Voigt, “Pharmazeutische Technologie” [Pharmaceutical Technology], Deutsche Apotheker Verlag, Stuttgart, 9th edition (2000), p. 163 ff).
Suppositories for rectal or vaginal use have also been used in pharmacy for a long time. These are dimensionally stable preparations which melt at body temperature or slowly dissolve in aqueous medium (Rudolf Voigt, “Pharmazeutische Technologie” [Pharmaceutical Technology], Deutsche Apotheker Verlag, Stuttgart, 9th edition (2000), p. 267 ff). They can be produced by molding or compression. Depending on the manufacturing process, besides the customary pharmaceutical requirements, such as good tolerability and compatibility with the active ingredient and durability, further requirements are placed on the raw materials used, such as, for example, small differences between the melting point and solidification point, and between the yield point and clear melting point and at least kinetic stability of the crystal modification formed first. Suppositories for topical use have not hitherto been described.
Moreover, the prior art discloses pharmaceutical capsules, for example soft and hard gelatin capsules, which consist of an envelope of gelatin and glycerol, and sometimes dyes, and a liquid, pasty or particulate filling. The method of producing these capsules known for many years takes place, for example, in accordance with the so-called rotary-die system (Seifen-Öle-Fette-Wachse, Vol. 113; No. 3/1987, page 67 ff). These gelatin capsules dissolve when swallowed in the gastrointestinal tract and release their ingredients. Since it is directly possible to produce capsules in different sizes and shapes, use is limited not just to peroral application forms (Rudolf Voigt, “Pharmazeutische Technologie” [Pharmaceutical Technology], Deutsche Apotheker Verlag, Stuttgart, 9th edition (2000), p. 543ff). Oral absorption can be achieved through suckable capsules. They are hollow on the inside and have a wall which is three times thicker than that of other capsules. The active ingredient is incorporated here in the gelatin envelope. A further example is nitroglycerol chewable capsules (bite-through capsules), which likewise allow rapid absorption of the active ingredient via the oral mucosa. Furthermore, individually dosed medicaments can be applied after puncturing or cutting the tubular ointment capsules by squeezing out the contents (percutaneous application of nitroglycerol heart ointment).
From the food sector, for example, various preparations which are solid at room temperature are known which melt at body temperature. These are mostly vegetable fat preparations, particularly based on cocoa butter and shea butter (chocolate) or W/O emulsions of hydrogenated vegetable fats and free fatty acids (margarine). As “ice confection”, preparations are known in which a moderately high enthalpy of melt has to be applied and which therefore have a cooling effect in the mouth.
Moreover, pralines are known which comprise liquid or pasty ingredients in a dimensionally stable chocolate coating. The coating melts during sucking or biting-through in the mouth or after swallowing.
In the cosmetics sector, the so-called bath beads are known whose envelope, e.g. made of gelatin, dissolves in hot or warm bathwater without leaving a residue and releases its contents, for example surfactant preparations, emulsions, lipids, dyes and/or perfumes, into the bathwater. Since the envelope consists of gelatin, the product must not contain water, otherwise the envelope would soften during storage.
A second group of cosmetic capsules covers all products for which the capsule envelope represents only a container for the single dose and use and whose envelope is left behind following use. A disadvantage with this is that the envelope which is left behind is troublesome and in addition has to be disposed of.
Numerous cosmetic and/or dermatological active ingredients are unstable toward certain influences such as moisture, low or high pH values and oxygen or light. There has therefore been no lack of attempts to remove the specified undesired environmental influences from such active ingredients in such a way that the active ingredients are nevertheless released upon application. One way of achieving this aim is the microencapsulation or nanoencapsulation of active ingredients. The encapsulation material as carrier system for the active ingredients allows them to be incorporated into suitable preparations in a form protected against environmental influences without the user being able to perceive the capsules during product application.
The aim of such an encapsulation is, for example, to produce wax particles containing active ingredient in the micrometer range (1-250 μm) which can be incorporated into common pasty or liquid cosmetic preparations. It is hitherto not known to produce, store and topically use these microcapsules as an independent cosmetic preparation.
There are a number of approaches for encapsulating cosmetic active ingredients. For example, the liposomal encapsulation of medicaments, which is intended to lead to a slow release of active ingredient, is known. These are essentially spherical vesicles containing active ingredient and surrounded by phospholipids or other amphiphilic agents, the so-called liposomes. The long-term stability of such structures, however, is poor.
Nanoparticles are solid particles with particle sizes of from 20 to 500 nm. Sometimes, larger particles with diameters up to 1000 nm are also regarded as being nanoparticles. Particles of this type generally consist of polymers and have cavities or form an envelope so that guest molecules can stay inside them, these molecules being enclosed or adsorbed. These guest molecules are then slowly released upon application of the nanoparticle-containing product. Solid lipid nanoparticles, which comprise active ingredients distributed within a matrix made of solid lipids behave in a similar way. The size of the particles is comparable with that of nanoparticles.
Numerous methods are known for encapsulating pharmaceutical or cosmetic active ingredients for controlling active ingredient release or the stable incorporation in preparations.
European patent application EP 1064911 or EP 1064912 discloses microcapsules comprising active ingredients and having a diameter of from 0.1 to 5 mm which are obtained by preparing a matrix from gel formers, chitosan and active ingredient, and adding this dropwise to aqueous solutions of anionic polymers. In so doing, a membrane forms from chitosan and anionic polymer and surrounds the active ingredient solution. These microparticles are then in turn used as constituent of customary cosmetic preparations. General information regarding encapsulation techniques with chitosan can be found in Journal of Microencapsulation 14, pages 689-711 (1997).
Mostly lipophilic active ingredients encapsulated in lipid particles are known per se to the person skilled in the art. For example, EP 167825, DE 100 59 668, DE 199 45 203, EP 0934743, WO 94/20072, WO 00/10522 and WO 00/67728 describe lipid particles charged with active ingredient. However, these documents were unable to solve the problem of providing spherical preparations with or without cosmetic ingredients which can be prepared, stored and applied topically as an independent cosmetic preparation.
Lip care sticks made of W/O emulsions which are solid at room temperature are described, for example, in DE 10148313. This technology described therein is hereby subject-matter of the present invention. The emulsions according to DE 10148313 do not become liquid upon distribution or rubbing on the skin, the emulsion is merely rubbed off onto the area of application, particularly the lips. Liquefaction of the preparations described therein is even undesired since, to care for the lips, the applied material should remain for as long as possible at the site of application and not, for example, run off.
It is an object of the present invention to provide a cosmetic preparation which is in the form of dimensionally stable spheres, is thus individually portionable and can be distributed as a whole on the skin. In this connection, no residues, capsule material etc. at all should be left behind which would, if appropriate, have to be disposed of separately or remain visible on the skin. In particular, it is the object of the present invention to provide a cosmetic preparation which constitutes a novel cosmetic product form and offers the user a novel application experience and broadens the application spectrum of skincare and/or hair care products.